Welp, if you're giving me this solution, then I'd assume you know it's possible and you know how to do it. So, how do I port my Electron project over to PWA?
You said you've exported a web version, so yes, it most likely should be possible, though it might take a while. You should just need to add a script and some meta tags to the HTML, and add a few other small files (a manifest, a service worker and some icons), and then you must host the file on a secure website (ie. https, not just http - getting that set up is actually the hardest part).
When I was doing it (not starting with a GDevelop app), the most helpful tutorials I found were these:
https://developer.mozilla.org/en-US/docs/Web/Progressive_web_apps/Installable_PW...
https://medium.com/james-johnson/a-simple-progressive-web-app-tutorial-f9708e5f2...
https://web.dev/offline-cookbook/
Anyway, I'm not saying it's definitely the way to go, but it might be worth looking into.